The current contract has been extended on a temporary basis since expiring last October and is in effect until Thursday. If the pact isn't extended again, the union could call a strike or the company could authorize a lockout.

CenturyLink is disappointed in the vote but believes the contract was fair given the competitive market, spokesman Mark Molzen said.

CenturyLink said the proposed contract would reduce pay disparities and offer employees pay and benefits aligned with similar jobs in their markets. Along with wage increases, it included a commitment from the company to return jobs that were outsourced, the company said.

In a letter to members dated Sept. 5, union leaders outlined other possible options besides a strike or lockout if the tentative deal was rejected. The parties could return to the bargaining table, or the company could terminate the contract that had been extended and implement the tentative agreement or portions of it.

"If we went on strike, it would be classified as an economic strike meaning we could be permanently replaced," according to a letter signed by CWA District 7 vice president Mary Taylor and bargaining committee chair Reed Roberts.

The last time CWA-represented employees for the company went on strike was in 1998. The 15-day work stoppage cost CenturyLink predecessor US West, which merged with Qwest in 2000, an estimated $20 million.

CenturyLink and CWA District 7 opened negotiations on a new contract in August 2012.